This is a plot to show that the squeezing performance has been nice and consistent since work in October, including the crystal move, and getting both the ASC and SQZ angle servos working together. This seems to be helping our range to be more consistent over the last few months as well.
Sheila, Camilla. Last done in 80451, followed those instructions.
Before translating the crystal, we reduced the green H1:SQZ-SHG_LAUNCH_DC_POWERMON power from 30mW down to 6mW. After we finished, we brought this up to 15mW and still could lock the OPO with 80uW on H1:SQZ-OPO_TRANS_LF_OUTPUT and around 6 on the ISS controlmon. Meaning our losses reduced significantly.
We moved from the 3rd spot from the left photo to the 4th spot from the left photo ( 34 x steps of 50 to the right and then 19 x steps of 10 to the right). We have previously used the 2nd, 3rd, and 5th spots from the left, there is 6 spots in total.
Measured NLG to be 8.8 (0.0787/0.00892, 76542). This is lower than what we usually run with 11 to 17 so means that this new spot has less losses but a worse NLG.
FDS is the same but ASQZ lower. Shiela said that this good and is expected with lower losses and mean there can be less mis-rotated ASQZ injected. Plot attached.
Tagging OpsInfo: This change will mean that for the next week or so we'll need to more regularly adjust the OPO TEC temperature, instructions are in 80461. Should be done pro-actively when relocking and if range is low in observing. If you adjust while in Observing, please tag Detchar in your alog.
Operators, please actually go out of Observing to make this temperature change (no need for pre-approval from me, if the range check indicates it needs doing).
This alog from October points out that these temperature changes are so successful at improving our range so quickly that it causes some problems for the astrophysical searches. This is entirely mitigated if we pop out of Observe during the change, then back in when the change is complete.
Mon Jan 06 10:14:22 2025 INFO: Fill completed in 14min 19secs
Gerardo confirmed a good fill curbside.
TCtrip = -50C, TCmins [-82C, -27C]. OAT (3C, 38F)
Famis 28386
Last weeks's In-Lock SUS Charge Measurements: Injections were not made on Tuesday Dec 31st 2024.
TITLE: 01/06 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 158Mpc
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 8mph Gusts, 6mph 3min avg
Primary useism: 0.06 μm/s
Secondary useism: 0.68 μm/s
QUICK SUMMARY:
Observing and have been Locked for over 5 hours. Secondary microseism looks like it's been creeping up.
TITLE: 01/06 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 165Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Quiet night, we stayed locked the whole shift, 10.5 hours as of 06:00 UTC. 2ndary microseism has risen rapidly over the past 3 hours.
LOG: No log.
TITLE: 01/06 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 160Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Currently Observing and have been locked for 5 hours. One lockloss today due to an EQ, but relocking was easy. The only problem I ran into was during initial alignment SRY couldn't catch, but I just had us go through SR2 align again and then we were fine. No other intervention was needed from me.
LOG:
15:30 Relocking and at LOCKING_ARMS_GREEN
16:34 NOMINAL_LOW_NOISE
16:38 Observing
17:37 Lockloss due to earthquake
- Ran an initial alignment
- Was having trouble with SRY so I reran SR2 and that worked
19:30 NOMINAL_LOW_NOISE
19:32 Observing
TITLE: 01/06 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 159Mpc
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 3mph Gusts, 2mph 3min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.35 μm/s
QUICK SUMMARY:
Sun Jan 05 10:13:05 2025 INFO: Fill completed in 13min 2secs
TCtrip -50C, TCmins [-64, -34] OAT (4C, 38F).
Est. TCA-min was -62.
Lockloss @ 01/05 17:37 UTC due to earthquake
Waiting for earth to calm down before trying to relock.
19:32 Observing
TITLE: 01/05 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 4mph Gusts, 2mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.38 μm/s
QUICK SUMMARY:
Currently relocking and at FIND_IR. We had been locked for 14.5 hours before having a lockloss a bit ago at 01/05 15:17UTC
16:38 UTC Back to Observing
TITLE: 01/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 158Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: We've been locked for over 5 hours.
LOG: No log
"pump fiber rej power in ham7 high, align fiber pol on sqt0" notification on SQZ_OPO_LR
00:46 UTC observing
Reduced the pump rejected power H1:SQZ-SHG_FIBR_REJECTED_DC_POWER: using the two pico waveplates on the SQZT0 SHG to OPO path H1:SYS-MOTION_C_PICO_I_MOTOR_3_{X/Y}_POSITION, scope on SQZT0 "! fiber pol". Reduced SHG_FIBR_REJECTED from 0.4 to 0.03mW.
TITLE: 01/05 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Currently relocking and at MAX_POWER. Most of today we were Locked and Observing, but this one lockloss so far hasn't been too bad to relock from. Only issue I had was that ALSY took forever to lock and I ended up having to adjust it manually just a couple of steps.
LOG:
19:30 Dropped Observing and went to NLN_CAL_MEAS for calibration measurements
20:04 Back to NLN and Observing
22:50 Lockloss
- I had to touch ALSY because it couldn't lock after 30 minutes of trying, even with SCAN_ALIGNMENT. Just needed to be adjusted a tiny bit in P
- Ran an initial alignment
- Continued relocking
TITLE: 01/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 4mph Gusts, 2mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.36 μm/s
QUICK SUMMARY:
"pump fiber rej power in ham7 high, align fiber pol on sqt0" notification on SQZ_OPO_LR
Lockloss @ 01/04/25 22:50 UTC after 18.5 hours locked. Not sure of the cause yet.
00:46 UTC Observing
This alog follows up LHO:81769 where I calibrated the ASC drives to test mass motion for all eight arm ASC control loops. Now, I have taken the noise budget injections that we run to measure the ASC coupling to DARM, and used that to calibrate an angle-to-length coupling function in mm/rad. I have only done this for the HARD loops because the SOFT loops do not couple very strongly to DARM (notable exception to CSOFT P, which I will follow up on).
The noise budget code uses an excess power projection to DARM, but instead I chose to measure the linear transfer function. The coherence is just ok, so I think a good follow up is to remeasure the coupling again and drive a bit harder/average longer (these are 60 second measurements). This plot shows the noise budget injection into calibrated DARM/ASC PUM drive [m/Nm] transfer function, and the coherence of the measurement.
I followed a similar calibration procedure to my previous alog:
I did not apply the drive matrix here, so the calibration is into ETM motion only (factor of +/-1), whereas the calibration into ITM motion would have an additional +/- 0.74 (+/- 0.72 for yaw) applied.
HARD Pitch Angle to Length coupling plot
HARD Yaw Angle to Length coupling plot
Overall, the best-measured DOF here is CHARD Y. In both CHARD Y and DHARD Y, there seem to be two clear coupling regions: one fairly flat region above 20 Hz in CHARD Y and above 30 Hz in DHARD Y, reaching between 20-30 mm/rad. Below, there is a steep coupling. This is reminiscient of the coupling that Gabriele, Louis, and I measured back in March and tried to mitigate with A2L and WFS offset. We found that we could reduce the flatter coupling in DHARD Y by adjusting the A2L gain, and the steeper coupling by applying a small offset in AS WFS A yaw DC. We are currently not running with that WFS offset. The yaw coupling suggests that we have some sort of miscentering on both the REFL and AS WFS which causes a steep low frequency coupling which is less sensitive to beam centering on the test mass (as shown by the A2L tests); meanwhile, the flat coupling is sensitive to beam miscentering on the test mass, which is expected (see e.g. T0900511).
The pitch coupling has the worst coherence here, but the coupling is certainly not flat. It appears to be rising with about f^4 at high frequency. I have a hard time understanding what could cause that. There is also possibly a similar steep coupling at low frequency like the yaw coupling, but the coherence is so poor it's hard to see.
Assuming that I have my calibration factors correct here (please don't assume this! check my work!), this suggests that the beam miscentering is higher than 1 mm everywhere and possibly up to 30 mm on the ETMs (remember this would be ~25% lower on the ITMs). This seems very large, so I'm hoping that there is another errant factor of two or something somewhere.
My code for both the calibrated motion and calibrated coupling is in a git repo here: https://git.ligo.org/ecapote/ASC_calibration
Today I had a chance to rerun these injections so I could get better coherence, injection plot. I ran all the injections with the calibration lines off.
The pitch couplings now appear to be very flat, which is what we expect. However, they are very high (100 mm/rad !!) which seems nearly impossible.
The yaw couplings still show a strong frequency dependence below 30 Hz, and are flat above, and around 30-50 mm/rad, still large.
Whether or not the overall beam miscentering value is correct, this does indicate that there is some funny behavior in yaw only that causes two different alignment coupling responses. Since this is observed in both DHARD and CHARD, it could be something common to both (so maybe less likely to be related to the DARM offset light on the AS WFS).
I also ran a measurement of the CSOFT P coupling, injection plot. I was only able to get good coherence up to 30 Hz, but it seems to be fairly flat too, CSOFT P coupling.
Edit: updated coupling plots to include error shading based on the measurement coherence.
